Commit a6eaf966 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
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perf lock contention: Show full callstack with -v option 



Currently it shows a caller function for each entry, but users need to see
the full call stacks sometimes.  Use -v/--verbose option to do that.

  # perf lock con -a -b -v sleep 3
  Looking at the vmlinux_path (8 entries long)
  symsrc__init: cannot get elf header.
  Using /proc/kcore for kernel data
  Using /proc/kallsyms for symbols
   contended   total wait     max wait     avg wait         type   caller

           1     10.74 us     10.74 us     10.74 us     spinlock   __bpf_trace_contention_begin+0xb
                          0xffffffffc03b5c47  bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
                          0xffffffffc03b5c47  bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
                          0xffffffffbb8b8e75  bpf_trace_run2+0x35
                          0xffffffffbb7eab9b  __bpf_trace_contention_begin+0xb
                          0xffffffffbb7ebe75  queued_spin_lock_slowpath+0x1f5
                          0xffffffffbc1c26ff  _raw_spin_lock+0x1f
                          0xffffffffbb841015  tick_do_update_jiffies64+0x25
                          0xffffffffbb8409ee  tick_irq_enter+0x9e
           1      7.70 us      7.70 us      7.70 us     spinlock   __bpf_trace_contention_begin+0xb
                          0xffffffffc03b5c47  bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
                          0xffffffffc03b5c47  bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
                          0xffffffffbb8b8e75  bpf_trace_run2+0x35
                          0xffffffffbb7eab9b  __bpf_trace_contention_begin+0xb
                          0xffffffffbb7ebe75  queued_spin_lock_slowpath+0x1f5
                          0xffffffffbc1c26ff  _raw_spin_lock+0x1f
                          0xffffffffbb7bc27e  raw_spin_rq_lock_nested+0xe
                          0xffffffffbb7cef9c  load_balance+0x66c

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220912055314.744552-3-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 637522ce

tools/perf/builtin-lock.c

+47 −4
Original line number Diff line number Diff line
@@ -1014,6 +1014,27 @@ static u64 callchain_id(struct evsel *evsel, struct perf_sample *sample) 
	return hash;

}



static u64 *get_callstack(struct perf_sample *sample, int max_stack)

{

	u64 *callstack;

	u64 i;

	int c;



	callstack = calloc(max_stack, sizeof(*callstack));

	if (callstack == NULL)

		return NULL;



	for (i = 0, c = 0; i < sample->callchain->nr && c < max_stack; i++) {

		u64 ip = sample->callchain->ips[i];



		if (ip >= PERF_CONTEXT_MAX)

			continue;



		callstack[c++] = ip;

	}

	return callstack;

}



static int report_lock_contention_begin_event(struct evsel *evsel,

					      struct perf_sample *sample)

{
@@ -1040,6 +1061,12 @@ static int report_lock_contention_begin_event(struct evsel *evsel, 
		ls = lock_stat_findnew(key, caller, flags);

		if (!ls)

			return -ENOMEM;



		if (aggr_mode == LOCK_AGGR_CALLER && verbose) {

			ls->callstack = get_callstack(sample, CONTENTION_STACK_DEPTH);

			if (ls->callstack == NULL)

				return -ENOMEM;

		}

	}



	ts = thread_stat_findnew(sample->tid);
@@ -1443,7 +1470,7 @@ static void sort_contention_result(void) 
	sort_result();

}



static void print_contention_result(void)

static void print_contention_result(struct lock_contention *con)

{

	struct lock_stat *st;

	struct lock_key *key;
@@ -1482,6 +1509,22 @@ static void print_contention_result(void) 
		}



		pr_info("  %10s   %s\n", get_type_str(st), st->name);

		if (verbose) {

			struct map *kmap;

			struct symbol *sym;

			char buf[128];

			u64 ip;



			for (int i = 0; i < CONTENTION_STACK_DEPTH; i++) {

				if (!st->callstack || !st->callstack[i])

					break;



				ip = st->callstack[i];

				sym = machine__find_kernel_symbol(con->machine, ip, &kmap);

				get_symbol_name_offset(kmap, sym, ip, buf, sizeof(buf));

				pr_info("\t\t\t%#lx  %s\n", (unsigned long)ip, buf);

			}

		}

	}



	print_bad_events(bad, total);
@@ -1597,6 +1640,8 @@ static int __cmd_contention(int argc, const char **argv) 
		return PTR_ERR(session);

	}



	con.machine = &session->machines.host;



	/* for lock function check */

	symbol_conf.sort_by_name = true;

	symbol__init(&session->header.env);
@@ -1615,8 +1660,6 @@ static int __cmd_contention(int argc, const char **argv) 
		signal(SIGCHLD, sighandler);

		signal(SIGTERM, sighandler);



		con.machine = &session->machines.host;



		con.evlist = evlist__new();

		if (con.evlist == NULL) {

			err = -ENOMEM;
@@ -1688,7 +1731,7 @@ static int __cmd_contention(int argc, const char **argv) 
	setup_pager();



	sort_contention_result();

	print_contention_result();

	print_contention_result(&con);



out_delete:

	evlist__delete(con.evlist);

tools/perf/util/bpf_lock_contention.c

+9 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include "util/thread_map.h"

#include "util/lock-contention.h"

#include <linux/zalloc.h>

#include <linux/string.h>

#include <bpf/bpf.h>



#include "bpf_skel/lock_contention.skel.h"
@@ -171,6 +172,14 @@ int lock_contention_read(struct lock_contention *con) 
			return -1;

		}



		if (verbose) {

			st->callstack = memdup(stack_trace, sizeof(stack_trace));

			if (st->callstack == NULL) {

				free(st);

				return -1;

			}

		}



		hlist_add_head(&st->hash_entry, con->result);

		prev_key = key;

	}

tools/perf/util/lock-contention.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ struct lock_stat { 


	u64			addr;		/* address of lockdep_map, used as ID */

	char			*name;		/* for strcpy(), we cannot use const */

	u64			*callstack;



	unsigned int		nr_acquire;

	unsigned int		nr_acquired;